Moscow: Russia's parliament on Friday debated a controversial homophobic bill to fine and jail people for up to 15 days for coming out in public as gay.

Lawmakers expressed support while rejecting the bill in its current wording as not legally valid.

The bill proposed by two Communist MPs calls for a fine of up to 5,000 rubles ($65) for "public expression of non-traditional sexual relationships."

It calls for a harsher punishment of up 15 days in police cells for being openly gay in educational institutions or in those related to the arts and youth.

Gay and LGBT rights activist Nikolai Alexeyev holds a flare as he rides a quad-bike during an unauthorized gay rights activists rally in central Moscow in a file photo. AFP

The authors of the bill said in an accompanying note it was necessary because a law banning "propaganda" of gay relationships to minors signed by President Vladimir Putin in 2013, and internationally condemned, was "not effective enough."

One of them, Communist MP Ivan Nikitchuk told parliament he had "received hundreds of messages of support for the bill," waving a folder of letters and telegrams.

He condemned the "aggressive propaganda of Western culture and non-traditional values," and called homosexuality "a huge threat for society, a deadly threat."

The bill doesn't define what non-traditional sexual relationships are, but Nikitchuk told MPs they are "between adult men" while "traditional" relationships are between a man and a woman.

Nikitchuk, the 71-year-old deputy head of the parliament's natural resources committee, said last year the bill would only apply to gay men.

Lawmaker Viktor Shudegov of A Just Russia party spoke in support of the bill, adding he wanted a ban on gay people working in professions such as teaching.

"Let the West rot," he said in angry rhetoric.

"They will destroy themselves from within and we will survive, we must survive, so I back this bill."

The MPs debated the bill despite it's being already rejected by the committee on constitutional law because it is not possible to introduce punishments for actions not legally defined as an offence.

As homosexuality is not illegal in Russia this made it technically impossible to pass the bill and it was rejected unanimously.

But that may not be the end of it.

A representative of the constitutional law committee, Rustam Ishmukhametov of ruling United Russia party voiced support for the bill and the possibiity of a new version.

"As a lawmaker I also share this concern. I agree that possibly it would be worth further discussion of this bill, maybe to submit it in a reworked version," he said in parliament, quoted by TASS state news agency.